Micrographic characterization of three tropical fruits, Musa paradisii L., Physalis peruviana L. and Persea americana Mill., Significance in the definition of botanical quality of derived foods

Abstract

The tropical fruits Musa paradisii L., "banana", Persea americana Mill., "Avocado", and Physalis peruviana L., "aguaymanto" are berries used in the industry for different purposes, such as food, cosmetic and medicinal, among others. The aim of the present work was to define the micrographic identification pattern of these three tropical fruits. The micrographic method was applied, the techniques of which were: a. mild decoupling  with 5% NaOH solution at 100 ° C for 5 min and observation under the light microscope after washing; b. strong decoupling for woody material with 10% KOH at 100 ° C and then with 25% chromic acid for 30 to 60 min.; c. scraping with a sharp cutting element, taking part of the material (powder or wet) and observation; d.  histochemical reactions with Lugol to detect starch, Sudan III for lipids, 2% HCl to determine crystal types. The following indicators are proposed as characters of representative diagnostic value for bananas: oleoresins, raffidia and simple, eccentric starch grains and as complementary elements fibers; for aguaymanto: crystalline sands, simple and compound starch grains and lipid drops; for avocado: isodiametric sclereides, polyhedral crystals and lipid drops. These elements are useful and necessary to identify the presence of fruits of the species in derived products and thus verify their genuine character. It should be noted that applied microscopy is a scientific method, which turns out to be an adequate strategy to perform control and certify products derived from vegetables.